The present invention relates to oscillating sprinklers, and relates more particularly to the spray tube assembly for an oscillating sprinkler which comprises a spray tube and an inner tube inserted into the spray tube and turned to alternatively open and close the jet nozzles on the spray tube.
Various oscillating sprinklers have been developed for sprinkling water over the lawn. FIG. 1 shows an oscillating sprinkler according to the prior art which comprises a base and a spray tube mounted on the base and turned back and forth by an oscillating control device. When water is guided to the oscillating sprinkler, it is driven out of the spray tube through the jet nozzles on the spray tube when the spray tube is turned back and forth. Because the jet nozzles of the spray tube cannot be alternatively closed and opened, the water spraying area of the oscillating sprinkler is not adjustable. FIG. 2 shows another structure of oscillating sprinkler in which a polygonal sleeve is mounted around the spray tube, having a plurality of nozzle strips with jet nozzles at each side. By changing the angular position of the polygonal sleeve relative to the spray tube, the jet nozzles on the spray tube are alternatively opened and closed, and therefore the water spraying area of the oscillating sprinkler is adjusted. Because the nozzle strips are respectively fastened to the polygonal sleeve by a high-frequency heat sealing process, the complicated assembly process greatly increases the manufacturing cost of the oscillating sprinkler.